Revealing the Variation of Photodetectivity in MAPbI<sub>3</sub> and MAPb(I<sub>0.88</sub>Br<sub>0.12</sub>)<sub>3</sub> Single Crystal Based Photodetectors Under Electrical Poling-Induced Polarization
Apurba Mahapatra, Rohit D. Chavan, Mohammad Mahdi Tavakoli, Pawan Kumar, Abul Kalam, Daniel Prochowicz, Pankaj Yadav
Abstract
The use of electrical poling to induce polarization \npotential has been found to increase the photocurrent (Ilight) in \nhybrid perovskite-based devices; however, the origin of this process \nhas not been fully understood. Here, we study the effect of \nelectrical poling on the photodetection properties of self-powered \nphotodetectors (PDs) based on halide perovskites in two different \nphase structures (i.e., tetragonal and cubic). Specifically, extensive \ninvestigations are performed on the MAPbI3 (tetragonal) and \nMAPb(I0.88Br0.12)3 (cubic) single crystals (SCs). Our characterization \nresults revealed that the Ilight has increased by 2-fold during \nforward poling and decreased during reverse poling in both PDs. \nThe improved Ilight is caused by polarization induced ion migration, \nwhich builds remanent potential due to ion accumulation near \nmetal electrodes. The effect of this polarization was found to be greater in MAPbI3 PD as compared to MAPb(I0.88Br0.12)3 PD, which \ninfluences the interface band bending and reduces Schottky barrier height (SBH). This study highlights that the modification of \nSBH, which describes the potential energy barrier for electrons formed at a metal−semiconductor junction, can tune the \nphotocurrent and response time of PDs.